MAPPING OF BOTH AUTOSOMAL RECESSIVE AND DOMINANT VARIANTS OF PSEUDOXANTHOMA ELASTICUM TO CHROMOSOME 16P13.1

Pseudoxanthoma elasticum (PXE) is a classic inherited disorder of the elastic tissue characterized by progressive calcification of elastic f ibers with a pathognomonic histological appearance, The clinical manif estations of PXE typically involve the skin, the eye and the cardiovas cular system, resulting in skin lesions, decreased Vision and vascular disease, Clinically a more common autosomal recessive and a less comm on autosomal dominant pattern of inheritance, with high penetrance, ha ve been described; the estimated prevalence of the disease is 1 in 70 000 100 000. Previous failure to link the disease to any of several ca ndidate genes prompted us to conduct a genome-wide screen on a collect ion of 38 families with two or more affected siblings, using allele sh aring algorithms. Excess allele sharing was found on the short arm of chromosome 16 and confirmed by conventional linkage analysis, localizi ng the disease gene under a recessive model with a maximum two point l od score of 21.27 on chromosome 16p13.1, an area so far devoid of any obvious candidate genes. Under a dominant transmission pattern linkage with a maximum two point lod score of 14.53 was observed to the same region. Linkage heterogeneity analysis predicted the presence of allel ic heterogeneity with different Variants of a single gene that resides in this chromosomal region accounting for recessive and dominant form s of PXE.